Bilateral Internal Thoracic Artery Grafting Research Articles

Previous coronary stents do not increase early and long-term adverse outcomes in patients undergoing off-pump coronary artery bypass grafting: A propensity-matched comparison

The aim of our study was to compare the early and long-term outcomes of patients undergoing off-pump coronary artery bypass grafting (CABG) with and without previous coronary stents. Between September 2004 and September 2011, 269 patients with previous stents underwent first-time isolated off-pump CABG. These patients were compared with 897 patients without previous stent. A propensity score-matching analysis was performed to compare early and late outcomes between the groups. Mean follow-up time was 43.4 months after surgery. Patients with previous stents were more likely to be men (85.9% in the stent group vs 79.4% in the no-stent group; P=.022) and more likely to have prior myocardial infarction (60.2% vs 36.8%; P<.001). Mean number of anastomoses was lower in patients with previous stents than in patients without previous stents (4.0 vs 4.2; P=.037). There was no difference in the use of bilateral internal thoracic artery graft between the groups (88.8% vs 89.1%; P>.999). After propensity adjustment for preoperative characteristics, both operative death (0.7% vs 1.5%; P=.414) and the major complications rates (7.8% vs 7.5%; P=.869) were similar between the groups. The actuarial survival rate at 7 years was not different between the groups (87.2%±3.2% vs 84.8%±2.9%; P=.470). Furthermore, freedom from major adverse cardiac and cerebrovascular events at 7 years were similar between the groups (78.9%±3.8% vs 77.6%±3.3%; P=.811). Previous coronary stents do not increase early and long-term morbidity or mortality in patients undergoing off-pump CABG.

Toward zero: Deep sternal wound infection after 1001 consecutive coronary artery bypass procedures using arterial grafts: Implications for diabetic patients

Coronary artery bypass graft (CABG) surgery with arterial conduits is considered optimal. A deterrent to bilateral internal thoracic artery (BITA) grafting is the risk of deep sternal wound infection (DSWI). We introduced infection prevention measures sequentially, attempting to reduce DSWIs. The aim was to determine (1) if the absence of DSWIs in the last 469 of 1001 consecutive operations was significant; (2) which measures explained the change; and (3) the impact of diabetes. The measures included internal thoracic artery (ITA) skeletonization, no bone wax, wound irrigation, 1 observer per case, harmonic scalpel harvest of ITAs, vancomycin paste on sternal marrow, iodine-impregnated skin drapes, chlorhexidine-alcohol skin preparation, no BITA grafts in obese, diabetic women, more off-pump procedures, aseptic wound care, and marrow irrigation before sternal approximation. Mean age was 65±10.4 years, 78% were male, 34% had diabetes, and 34% were obese. The first 532 patients had 16 DSWIs (3%) and the subsequent 469 had none (P<.001). Analysis of the data suggested that the first 11 measures likely contributed to the absence of DSWI and less likely, the twelfth. Key measures were likely chlorhexidine-alcohol use and avoidance of BITAs in obese diabetic women who had a 10-fold higher DSWI rate than the other patients (21.4% vs 2.0%). Other diabetics, including obese men, had no increased risk of DSWI. The measures applied caused a substantial reduction in DSWIs. Key measures included the use of chlorhexidine-alcohol and avoidance of BITA grafting in obese diabetic females. These measures reduced DSWIs after BITA grafting in most diabetics.

The short-term outcome of bilateral internal thoracic artery use in patients undergoing off pump coronary bypass surgery

Purpose: The use of bilateral internal thoracic artery (BITA) grafting has shown a better survival benefit when compared to single internal thoracic artery (SITA) grafting. This study was undertaken to evaluate the short-term outcome of using BITA in patients undergoing off pump coronary bypass surgery.

Bilateral internal thoracic artery grafting for peripheral arterial disease patients

Peripheral arterial disease (PAD) is known to have a poor prognosis. Some reports have also described poor late results after coronary artery bypass grafting (CABG). However, there have been few reports about whether bilateral internal thoracic artery grafting improves the long-term survival of PAD patients after CABG. We performed this study to clarify whether or not this is the case. One hundred and thirty-six PAD patients who underwent elective CABG with two or more grafts were enrolled in this study. Patients were divided into two groups, 71 patients in the bilateral internal thoracic artery (BITA) group and 65 patients in the single internal thoracic artery (SITA) group. The maximum follow-up period was 19 years, with a mean of 5.7 ± 4.4 years. We investigated the long-term results based on three factors; survival, freedom from cardiac death, and freedom from cardiac events. The 3-, 5- and 10-year survival rates in the BITA group were 83.0, 74.2, and 43.1%, respectively. And those in the SITA group were 79.4, 67.7, and 32.3%, respectively. There were no significant differences between the two groups (p = 0.5843). There were also no statistically significant differences between the two groups in terms of the freedom from cardiac death (p = 0.8589) or in the freedom from cardiac events (p = 0.9445). No long-term advantage was observed for CABG with BITA in comparison to SITA alone in patients with PAD.

A meta-analysis of adjusted hazard ratios from 20 observational studies of bilateral versus single internal thoracic artery coronary artery bypass grafting

In 2001, a landmark meta-analysis of bilateral internal thoracic artery (BITA) versus single internal thoracic artery (SITA) coronary artery bypass grafting for long-term survival included 7 observational studies (only 3 of which reported adjusted hazard ratios [HRs]) enrolling approximately 16,000 patients. Updating the previous meta-analysis to determine whether BITA grafting reduces long-term mortality relative to SITA grafting, we exclusively abstracte, then combined in a meta-analysis, adjusted (not unadjusted) HRs from observational studies. MEDLINE and EMBASE were searched until September 2013. Eligible studies were observational studies of BITA versus SITA grafting and reporting an adjusted HR for long-term (≥4 years) mortality as an outcome. Meta-regression analyses were performed to determine whether the effects of BITA grafting were modulated by the prespecified factors. Twenty observational studies enrolling 70,897 patients were identified and included. A pooled analysis suggested a significant reduction in long-term mortality with BITA relative to SITA grafting (HR, 0.80; 95% confidence interval, 0.77 to 0.84). When data from 6 pedicled and 6 skeletonized internal thoracic artery studies were separately pooled, BITA grafting was associated with a statistically significant 26% and 16% reduction in mortality relative to SITA grafting, respectively (P for subgroup differences=.04). A meta-regression coefficient was significantly negative for the proportion of men (-0.00960; -0.01806 to -0.00114). Based on an updated meta-analysis of exclusive adjusted HRs from 20 observational studies enrolling more than 70,000 patients, BITA grafting seems to significantly reduce long-term mortality. As the proportion of men increases, BITA grafting is more beneficial in reducing mortality.

What Is the Best Proximal Anastomosis for the Free Right Internal Thoracic Artery during Bilateral Internal Thoracic Artery Revascularization? A Prospective, Randomized Study

Objective. Bilateral internal thoracic artery (BITA) grafting provides improved graft patency and potential survival advantage in selected patients as compared to single left internal thoracic artery (LITA) revascularization. The ideal functional BITA configuration remains controversial. Methods. Patients undergoing planned BITA revascularization with greater than 75% stenosis in both the left anterior descending artery (LAD) and in a circumflex branch were prospectively randomized to one of two proximal free right internal thoracic artery (RITA) connections directly off the aorta (Ao) (n = 12) or as a “t” graft off the LITA (t) (n = 12). The LITA was placed to the LAD in all cases, and the RITA was placed to a single lateral wall vessel. Intraoperative transit time flow measurements of all arterial grafts were performed, and RITA fractional flow parameters were compared between the 2 groups. Results. There were no differences in preoperative patient variables between the two groups. Cross-clamp times (91.5 + 15.3 versus 68.0 + 12.5 minutes, P < 0.01) and total cardiopulmonary bypass times (109.0 + 16.2 versus 85.0 + 15.1 minutes, P < 0.01) were shorter in the t group. The Ao group demonstrated significantly higher mean RITA flow (38.3 ± 13.5 versus 22.1 ± 9.5, P < 0.01), mean RITA conductance (flow/mean arterial pressure) (0.45 ± 0.16 versus 0.28 ± 0.11, P < 0.01), RITA fractional flow (0.52 ± 0.15 versus 0.36 ± 0.11, P < 0.01), and RITA fractional conductance (0.51 ± 0.15 versus 0.36 ± 0.11, P < 0.01) than the “t” grafted patients. Thirty-day mortality and wound infection were 0% for each group. Over an average of 42.8 + 6.6 months of followup there were no mortalities in either group. Repeat angiography were performed in 4 patients (33%) in the Ao group and 2 patients in the t group (16%). One occluded RITA graft and one ostial RITA stenosis were detected in the Ao group. Conclusions. Acute flow measurements indicate that the free RITA anastomosed to the aorta provides more acute fractional RITA flow than composite “t” grafting to the LITA. Longer-term angiographic and clinical followup are necessary to determine the consequences of these acute hemodynamic findings.

Outcomes of Off-Pump Coronary Bypass Grafting with the Bilateral Internal Thoracic Artery for Left Ventricular Dysfunction

This study evaluated the outcomes of off-pump coronary artery bypass surgery (OPCAB) with severe left ventricular dysfunction using composite bilateral internal thoracic artery grafting. From January 2001 to December 2008, 1,842 patients underwent primary isolated OPCAB with composite bilateral internal thoracic artery grafting. A total of 131 of these patients were diagnosed with a severely depressed preoperative left ventricle ejection fraction (LVEF) (≤0.35). These patient outcomes were compared with the outcomes of 830 patients that had mildly or moderately depressed LVEF (0.36 to 0.59) and 881 patients with normal LVEF (>0.6). The early mortality for patients with severe LVEF was 2.3%. The 3-yr and 7-yr survival rate for patients with severe LV dysfunction was 86.0% and 82.8%, respectively. Multivariate analysis showed that severe LV dysfunction EF increased the risk of all-cause death (P=0.012; hazard ratio [HR],2.14; 95% confidence interval [CI],1.19-3.88) and the risk of cardiac-related death (P=0.008; HR,3.38; 95% CI, 1.37-8.341). The study identified positive surgical outcomes of OPCAB, although severe LVEF was associated with two-fold increase in mortality risk compared with patients who had normal LVEF.

Harvesting bilateral internal thoracic arteries using a novel subxiphoid approach versus the conventional lateral thoracic approach—results of an experimental study

A new method was developed to harvest bilateral internal thoracic artery grafts using a subxiphoid approach and robotic assistance. The present study compared the potential utility of the subxiphoid method with that of the lateral thoracic approach. The first part of the study examined the optimal placement of the instrument ports to maximize the robotic arms' range of motion. The second part of the study examined the 2 approaches for harvesting bilateral internal thoracic arteries from pig carcasses. The obtained graft lengths and time needed to conduct each procedure were compared using the Mann-Whitney U test. The preliminary study suggested that optimal positioning of the instrument ports was achieved by placing the right and left instrument ports far apart and linearly arranging all the ports. Using this configuration, the subxiphoid approach yielded a left internal thoracic artery that was 11.7 ± 1.90 cm long compared with 9.17 ± 0.74 cm using the conventional approach (P=.0131). The right internal thoracic arteries (11.8 ± 1.69 cm) obtained using the subxiphoid approach were significantly longer than those obtained using the conventional approach (8.88 ± 0.58 cm). The time needed to harvest the right internal thoracic arteries (34.7 ± 8.14 minutes) was significantly shorter using the subxiphoid approach than using the conventional approach (52.3 ± 8.21 minutes). Because of the maximized lengths of the grafts and the duration of the procedure, therobot-assisted subxiphoid approach could be an effective method for performing minimally invasive myocardial revascularization in patients with multivessel disease.

Does the use of bilateral mammary artery grafts compared with the use of a single mammary artery graft offer a long-term survival benefit in patients undergoing coronary artery bypass surgery?

A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was: 'Does the use of bilateral mammary artery grafts compared with the use of a single mammary artery graft offer a long-term survival benefit in patients undergoing coronary artery bypass surgery?' Altogether 214 papers were found using the reported search, of which 13 represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. All the included studies were follow-up studies; eight studies used prospective data collection, and five studies collected the study data retrospectively. No randomized controlled trials were found. Nine of the 13 included papers used a propensity-score-matched comparison of the survival of bilateral mammary artery graft [or, bilateral internal thoracic artery (BITA) graft] patients vs single mammary artery graft [or, single internal thoracic artery (SITA) graft] patients. These studies consistently showed an enhanced survival of BITA patients compared with propensity-score-matched SITA patients. Three of the 13 included papers used Cox proportional hazards regression analysis to compare survival of BITA vs SITA patients; one larger study showed better crude survival of BITA patients, but did not identify BITA grafts as independent predictor of enhanced survival. The remaining two studies also did not identify BITA grafts as independent predictor of enhanced survival. One study only presented crude survival estimates of BITA vs SITA patients and therefore was of limited informative value. We conclude that the use of BITA grafts seems to offer a long-term survival benefit compared with a SITA graft for patients undergoing coronary artery bypass grafting surgery. Although randomized evidence is lacking, observational evidence supporting this hypothesis is mounting.

Bilateral internal thoracic artery grafting.

The effectiveness of the left internal mammary artery graft to the anterior descending coronary artery as a surgical strategy has been shown to improve the survival rate and decrease the risk of adverse cardiac events in patients undergoing coronary bypass surgery. These clinical benefits appear to be related to the superior short and long-term patency rates of the internal thoracic artery graft. Although the advantages of using of both internal thoracic arteries (ITA) for bypass grafting have taken longer to prove, recent results from multiple data sets now support these findings. The major advantage of bilateral ITA grafting appears to be improved survival rate, while the disadvantages of complex ITA grafting include the increased complexity of operation, and an increased risk of wound complications. While these short-term disadvantages have been mitigated in contemporary surgical practice, they have not eliminated. Bilateral ITA grafting should be considered the procedure of choice for patients undergoing coronary bypass surgery that have a predicted survival rate of longer than ten years.

Total arterial coronary revascularization-patient selection, stenoses, conduits, targets.

Graft patency determines prognosis in coronary artery bypass grafting (CABG). Numerous reports over the past 20 years have documented superior patencies and prognosis when multiple arterial grafts are used, yet less than 10% of CABG have multiple arterial grafts. Several conduits have been proposed, with varying degrees of success. Saphenous vein grafts (SVG) begin to fail with intimal hypertrophy and then atheroma after 5 years, with patency rates of 50% to 60% at 10 years, and <30% at 15 years. In contrast, left internal thoracic artery (LITA) patency is >95% at 10 years and >90% at 20 years. The radial artery is extremely versatile and can reach all territories, but is muscular and vulnerable to spasm and competitive flow. Similarly, the right gastroepiploic artery is also muscular, and is best suited to the posterior descending coronary artery, especially in reoperations and is also affected by competitive flow. In addition, bilateral internal thoracic artery grafting (BITA) grafts and total arterial revascularization (TACR) can be performed with identical perioperative mortality (1%) and perioperative morbidity to LITA + SVG. Importantly, survival is superior-85% to 90% at 10 years versus 75% to 80% respectively. BITA/TACR patients also suffer fewer late cardiac events and reoperations, with superior results for older patients, those requiring urgent surgery, diabetics, patients with renal dysfunction and in reoperations. Contraindications to BITA include obesity, insulin dependent diabetics, and severe chronic obstructive airways disease. As such, arterial grafts have better patencies and clinical results. BITA/TACR is often underutilized, but can be achieved in the majority of patients. Opportunities exist to enhance BITA/TACR use in CABG to the potential benefit of our patients.

EComment. Prevention of sternal wound infection

We read with great interest the article by Sakic et al. [1] assessing the efficacy of surgical modifications on the incidence of postoperative sternal complications after bilateral internal thoracic arteries (BITA) harvesting. In this single-center retrospective study, the authors demonstrated that using a skeletonized approach in patients receiving bilateral internal thoracic arteries with augmented sternal wires is effective in preventing sternal wound complications. As described by others, this series supports the claim that the risk of sternal infection can be reduced by performing internal thoracic artery harvested in a skeletonized manner. Deo et al. [2] conducted the first systematic review and meta-analysis to address the essential clinical question of whether BITA increases the risk of deep sternal wound infection in patients with diabetes; they concluded that the risk may be minimized using a skeletonized approach. The left internal thoracic artery to left anterior descending artery graft has long been established as the cornerstone of improved early and late outcomes in surgically-treated patients. An overwhelming wealth of evidence, mainly retrospective studies, demonstrated that the use of BITA as bypass grafts provided superior early survival and better event-free survival after coronary artery bypass grafting. The Arterial Revascularization Trial [3] is the only randomized study comparing the outcomes of single internal mammary artery (SITA) vs BITA, with a primary outcome of survival at 10 years, and results should be available in five years. The risk of sternal wound complications may need to be weighed against the long-term benefit of BITA grafts. It is, needless to say, that anterior mediastinitis is a rare but ominous complication after BITA harvesting, carrying a high risk of in-hospital mortality. Many factors have been suggested as responsible for postcardiotomy sternal wound infection, and investigations to prevent this dreaded complication are still considered as a greatly researched topic in cardiac surgery. Recently, Grauhan et al. [4] investigated the efficacy of a new commercially available negative pressure wound therapy system (Prevena Incision Management System; KCI, San Antonio, USA) as a dressing treatment to prevent sternal wound infection in obese patients undergoing cardiac surgery. They showed in a prospective study that the application of a special foam as a wound dressing immediately after skin closure and negative pressure of -125 mmHg for the first 6 to 7 days postoperatively significantly reduces the incidence of sternal infection in this high-risk patient population. The technique of skeletonization during BITA harvest preserves sternal microacirculation [5]; the immediate application of a negative-pressure wound dressing after suturing prevents the breakdown of skin sutures and seepage of bacteria into the deeper layers. These two different methods showed to be effective in reducing the likelihood of sternal wound infection, and should be considered in high-risk patients of sternal complications. Conflict of interest: none declared.

Bilateral internal thoracic artery grafting in insulin-treated diabetes

We sought to assess the risk and late outcome of bilateral internal thoracic artery grafting in eligible insulin-treated diabetic subsets. 147 insulin-treated diabetic patients undergoing arterial revascularization were grouped as: skeletonized bilateral internal thoracic artery (n = 83) or internal thoracic artery-radial artery (n = 64). Chronic lung disease or overweight and female constituted exclusion criteria for bilateral internal thoracic artery grafts. Patients who had bilateral internal thoracic artery grafts were younger and comprised fewer females. Left-sided bilateral internal thoracic artery configurations were predominantly applied. Despite mean hemoglobin A1c of 8.0% ± 1% (range, 7%-13.5%) respective rates of deep sternal infection in bilateral internal thoracic artery and radial artery patients were 1.2% and 0%; superficial wound infection occurred in 3.1% and 3.6%, respectively. One sternoplasty was performed. Bilateral internal thoracic artery grafting did not correlate with sternal complications (odds ratio = 2.24, 95%CI: 0.56-8.95, p = 0.256). Of the radial artery conduits, 98% were adequate, and procurement-site complications occurred in 3.1%. Follow-up was 2-58 months (median, 25 months). Five-year survival was comparable in the 2 groups (p = 0.360). Bilateral internal thoracic artery grafting did not reduce late major adverse cardiac events (p = 0.729) or late mortality (p = 0.384). Skeletonized bilateral internal thoracic artery grafts can be used with acceptable risk in a substantial portion of insulin-treated diabetic patients, so it should not be automatically denied, but the choice of such grafts is not associated with midterm cardiac benefits.

Circulation: Clinical Summaries

<i>Circulation:</i> Clinical Summaries

Simple adaptations of surgical technique to critically reduce the risk of postoperative sternal complications in patients receiving bilateral internal thoracic arteries

Limited blood supply to the thoracic chest wall is a known risk factor for sternal wound complications after CABG. Therefore, bilateral internal thoracic arteries are still rarely utilized despite their proven superior graft patency. The aim of our study was to analyse whether modification of the surgical technique is able to limit the risk of sternal wound complications in patients receiving bilateral internal thoracic artery grafting. All 418 non-emergent CABG patients receiving bilateral internal thoracic artery CABG procedures (BITA) from January 2001 to January 2012 were analysed for sternal wound complications. Surgical technique together with known risk factors and relevant comorbidity were analysed for their effect on the occurrence of sternal wound complications by means of multivariate logistic regression analysis. Sternal wound complications occurred in 25 patients (5.9%), with a sternal dehiscence rate of 2.4% (10 patients). In multivariate analysis, diabetes (odds ratio [OR]: 4.8, 95% CI: 1.9-11.7, P=0.001), but not obesity (OR: 1.6, 95% CI: 0.7-4.2, P=0.28) or chronic obstructive pulmonary disease (OR: 2.2, 95% CI: 0.87-5.6, P=0.1) was a relevant comorbid condition for sternal complications. Skeletonization of ITA grafts (OR: 0.17, 95% CI: 0.06-0.5, P=0.001) and the augmented use of sternal wires (OR: 0.24, 95% CI: 0.06-0.95, P=0.04) were highly effective in preventing sternal complications. The use of platelet-enriched-fibrin glue (PRF) sealant, however, was associated with more superficial sternal infections (OR: 3.7, 95% CI: 1.3-10.5, P=0.02). Adjusted for common risk factors, skeletonization of BITA grafts together with augmented sternal wires is effective in preventing sternal complications. The use of PRF sealant, however, increased the risk for superficial wound complications.

Should Bilateral Internal Thoracic Artery Grafting Be Used in Elderly Patients Undergoing Coronary Artery Bypass Grafting?

Although bilateral internal thoracic artery grafting is associated with improved survival, the use of this technique in the elderly is controversial because of their increased surgical risk and shorter life expectancy. The purpose of this study was to evaluate the effect of age on outcome of patients undergoing bilateral internal thoracic artery grafting. Between 1996 and 2001, 1714 consecutive patients underwent skeletonized bilateral internal thoracic artery grafting, of whom 748 were ≤65 years of age, 688 were between 65 and 75 years of age, and 278 were ≥75 years of age. Operative mortality of the 3 age groups (1.2%, 4.1%, and 5.8%, respectively) was lower than the logistic EuroSCORE predicted mortality (3.9%, 6.5%, and 9.3%, respectively; P<0.001). There were no significant differences among the groups in occurrence of sternal infection (1.3%, 2.6%, and 1.4%, respectively; P=0.171). Mean follow-up was 11.5 years. Kaplan-Meier 10-year survival for patients ≤65, 65 to 75, and >75 years of age was 85%, 65%, and 40%, respectively (P<0.001). These rates were better than the corresponding predicted Charlson Comorbidity Index survival rates (68%, 37%, and 20%, respectively; P<0.001 for all age groups), approaching survival of the sex- and age-matched general population (90%, 70%, and 41%, respectively). Age ≤65 years (hazard ratio, 0.232; 95% confidence interval, 0.188-0.288) and age 65 to 75 years (hazard ratio, 0.499; 95% confidence interval, 0.414-0.602) were independent predictors of improved survival (Cox model). Bilateral internal thoracic artery grafting should be considered in patients >65 years of age because of the significant survival benefit obtained with this surgical technique with no additional risk of sternal wound infection related to age.

Is the second internal thoracic artery better than the radial artery in total arterial off-pump coronary artery bypass grafting? A propensity score–matched follow-up study

The aim of our study was to evaluate the long-term outcome of patients exclusively undergoing total arterial revascularization off-pump coronary artery bypass grafting and to compare the performance of the radial artery and the right internal thoracic artery as a second conduit. We studied a consecutive series of 1700 patients undergoing off-pump coronary artery bypass grafting, receiving a radial artery or right internal thoracic artery as a second graft for total arterial revascularization, between 2003 and 2010. A total of 1447 patients (85.11%) received bilateral internal thoracic artery grafting, and 253 patients (14.89%) received left internal thoracic artery and radial artery grafting. A propensity score-matched analysis was performed to compare the 2 groups, bilateral internal thoracic artery and left internal thoracic artery and radial artery, relative to overall survival, morbidity, and combined end points event-free survival. Hazard ratios (HRs) and their 95% confidence intervals (CIs) were estimated by Cox regression. In the full unmatched patient population, the postoperative survival (HR, 0.59; 95% CI, 0.38-0.92; P = .021), incidence of reintervention/readmission (HR, 0.42; 95% CI, 0.28-0.61; P < .001), and combined end points (HR, 0.47; 95% CI, 0.35-0.63; P < .001) were significantly better in the bilateral internal thoracic artery group. In the propensity score-matched patient population, the incidence of reintervention/readmission (HR, 0.40; 95% CI, 0.18-0.88; P = .02) and combined end points (HR, 0.54; 95% CI, 0.32-0.92; P = .02) were significantly better in the bilateral internal thoracic artery group compared with the left internal thoracic artery-radial artery group. The results of our study provide evidence for the superiority of the right internal thoracic artery graft compared with the radial artery as a second conduit in total arterial revascularization off-pump coronary artery bypass grafting.

The Choice of the Second Graft

Coronary artery bypass surgery was first described 50 years ago (see Chapter 1). During this pioneering era, there were few discussions on which graft to use, with SVGs used exclusively for the first 20 years. Today, all cardiac surgeons are daily face the difficult choice of which graft to use for a selected patient. The choice of conduits depends on several factors, such as the patient’s intrinsic characteristics (age, body mass index, diabetes, pulmonary function, peripheral vascular disease, saphenous vein quality) and extrinsic characteristics (elective or urgent). Additionally, the characteristics of the coronary lesion, including the degree of stenosis, the minimum lumen diameter (MLD), and the fractional flow reserve (FFR) impact the choice of conduits. Even after the graft choice has been made, the manner of using it is still controversial. Some researchers propose in situ graft use, while others prefer free grafts use. When used free, the choice must be made to reimplant the graft in the aorta or in another graft in a composite fashion. The composite assembly is also debated: is it preferable to use a T or a Y shape, and where do we perform this crucial anastomosis? When used in situ, there is no evidence that it is better to use the right internal thoracic artery (ITA) on the left anterior descending (LAD) artery crossing the midline or through the transverse sinus to a first marginal. Moreover, some researchers suggest using one graft per distal anastomosis, while others prefer sequential anastomosis. After patient characteristics, the most important consideration is the coronary lesion itself. Most of the surgical literature on graft patency is based on visual inspection for coronary lesion evaluation. Cardiologists have tried to find a more accurate method to evaluate the severity of the coronary lesion (quantitative coronary angiography (QCA), FFR); unfortunately, these solutions have not been applied to the evaluation of graft performance. Historically, graft patency evaluation has been performed to evaluate the SVG. Since arterial conduits display a totally different endothelial response to shear stress and competitive flow, these historical definitions have become obsolete, leading to new concepts such as “graft functioning.” Moreover, in contradiction to the evidence-based medical literature, there are few evidence-based cardiac surgery reports. Indeed, most of the graft patency literature is retrospective, with few systematic angiographic controls. Most control studies were symptom-driven, leading to a false evaluation of the conduit performance. Recent studies have promoted the use of less-invasive graft evaluations but without evidence of a good correlation with gold-standard angiography. In addition to all discussions regarding graft choice, there is one last powerful factor: “The Surgeon.” Each cardiac surgeon with a given mentorship background is more prone to use a certain graft type even if there is evidence for better performance of another graft. The best example of this phenomenon is the rate of bilateral ITA (BITA) grafting in the USA: 5%, whereas some American surgeons have dedicated their careers to convincing their colleagues that two ITAs are better then one. On the other hand, some European surgeons use BITA in all ages (> 80 years) and without careful evaluation of the coronary lesion. Due to the lack of a clear answer to the question of which graft to use in a specific patient, we decided to investigate the different grafts we used daily: right and left ITA (RITA and LITA, respectively), SVG, and also the right gastroepiploic artery (RGEA). For this purpose, we started 2 prospective randomized trials in 2003 with systematic 6 months functional evaluation. We also performed systematic 6 months and 3 years angiographic evaluation. In the first trial, we studied the various BITA configurations possible to revascularize the left coronary system (Annex 1). In the second, we compared the RGEA versus SVG to revascularize the right coronary artery (RCA) (Annex 2). In addition to these 2 majors trials we analyzed a subgroup of patients with composite Y arterial or venous graft configuration. We used for the first time in literature the FFR in bypass graft to assess the efficiency of this type of assembling (Annex 3-4). We also compared the vasomotion of the free RITA reimplanted in the in-situ LITA with a specific endothelial vasodilatator (Substance P) (Annex 5). Afterwards we analyzed the causes of non-functioning of the free RITA (Annex 6). During the same period, we realized the same analysis with the in-situ LITA and RITA graft (Annex 7). Finally, we analyzed more carefully the coronary lesion with the QCA in order to identify if there was a correlation between the lesion and the graft patency and evaluated a new method to redefine graft patency in relation to the arterial grafting (Annex 2-8-9).

Long-Term Outcomes after Off-Pump Coronary Artery Bypass Grafting in Left Ventricular Dysfunction

We assessed the long-term clinical, angiographic, and echocardiographic outcomes of patients with left ventricular dysfunction (ejection fraction ≤40%) who underwent isolated off-pump coronary artery bypass grafting. One hundred sixty one patients were included. Mean age was 67.2 ± 11.4 years, and 20 patients (12.4%) were female. Eighty-eight patients (54.7%) were New York Heart Association functional class 3 or 4. Early postoperative and follow-up angiography and echocardiography findings were analyzed, and mid-term survival rates (mean follow-up 40.7 ± 25.6 months) were calculated. Mean number of distal anastomoses was 4.4 ± 1.3. Bilateral internal thoracic artery grafts were used in 84.5% of patients. Operative mortality was 2.5%. Early patency rate of anastomoses was 98.3%. Early postoperative ejection fraction improved from 33.1 ± 5.6% preoperatively to 36.9 ± 9.5% (p <0.001). Seven-year survival rate was 73.9 ± 5.3%, and freedom from cardiac events rate was 68.5 ± 5.2%. One-year patency rate of anastomoses was 85.8%. Follow-up ejection fraction was 39.1 ± 10.7% (p <0.001). Early and long-term outcomes of off-pump coronary artery bypass grafting in patients with left ventricular dysfunction were favorable, including early postoperative and follow-up patency rates of anastomoses and echocardiographic recovery of ejection fraction.

No-Touch Aorta Off-Pump Coronary Bypass Operation: Arteriovenous Composite Grafts May Be Used as a Last Resort

Off-pump coronary artery bypass (OPCAB) operations with bilateral internal thoracic artery (BITA) or left internal thoracic artery (LITA) and radial artery (RA) in a Y-graft configuration achieves adequate myocardial revascularization while avoiding manipulation of the ascending aorta. The purpose of our study was to determine if saphenous veins can be used as composite grafts with the LITA as a last resort. Multivessel OPCAB without aortic manipulation was performed in 564 patients between February 2002 and October 2010. Patients receiving a LITA-vein composite graft (n = 62) were older and had more emergency procedures, renal insufficiency, peripheral vascular disease and therefore a higher logistic EuroSCORE predicted risk of mortality (all p < 0.001) than did patients who underwent BITA and LITA-RA grafts. Overall 30-day mortality was 1.1%: 6.5% in patients who received LITA-vein grafts and 0.5% in both total arterial groups (p = 0.001). Neurologic events occurred in 3.2%, 0.7%, and 0.5% of patients, respectively (p = 0.3). No patient who received a LITA-vein graft experienced perioperative myocardial infarction (MI). Patients in the total arterial graft groups had better 5-year survival (> 90%) and freedom from major adverse cardiovascular and cerebrovascular events (≥ 80%) than did patients who received LITA-vein grafts (74 ± 7.8% and 62.5 ± 8.1%, respectively). However there was no difference in the 3 groups with respect to freedom from MI and repeat revascularization. LITA-vein composite graft use is associated with a lower survival and higher complication rate, probably because of the higher patient risk profile. LITA-vein composite grafts may be used as a last resort in selected patients undergoing OPCAB operations without manipulation of the aorta when arterial grafts are not available or recommended.